<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>基本选择器</title>
    <style>
        div{
            color: red;
        }
        .cls{
            color: blue;
        }
        #d{
            color: green;
        }
    </style>

</head>
<body>
<div>元素选择器</div>
<div class="cls">类选择器</div>
<div id="d">id选择器</div>


</body>
</html>